User Manual

HD44780U
15
• Programming character patterns
This section explains the correspondence between addresses and data used to program character patterns
in EPROM. The HD44780U character generator ROM can generate 208 5 × 8 dot character patterns and
32 5 × 10 dot character patterns for a total of 240 different character patterns.
 Character patterns
EPROM address data and character pattern data correspond with each other to form a 5 × 8 or 5 ×
10 dot character pattern (Tables 2 and 3).
Table 2 Example of Correspondence between EPROM Address Data and Character Pattern
(5 × 8 Dots)
Data
O4 O3 O2 O1 O0
0 0 0 1
0 0 1 0
0 0 1 1
0 1 0 0
0 1 1 0 0 0 1 0
EPROM Address
Character code
Line
position
LSB
0 1 0 1
0 1 1 0
0 1 1 1
0 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
1 0 0 0
1 1 0 0 1
1 0 0 0 1
1 0 0 0 1
1 0 0 0 0
1 0 0 0 0
1 0 1 1 0
Cursor position
1 1 1 1 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
A11
Notes: 1. EPROM addresses A11 to A4 correspond to a character code.
2. EPROM addresses A3 to A0 specify a line position of the character pattern.
3. EPROM data O4 to O0 correspond to character pattern data.
4. EPROM data O5 to O7 must be specified as 0.
5. A lit display position (black) corresponds to a 1.
6. Line 9 and the following lines must be blanked with 0s for a 5 × 8 dot character fonts.